Coated article and method for making the same

ABSTRACT

A coated article includes a substrate, an anti-corrosion layer formed on the substrate, and a decorative layer formed on the anti-corrosion layer. The anti-corrosion layer is an amorphous alloy layer containing elements of iron, chromium, boron and M, wherein M is one or more selected from the group consisting of phosphorus, carbon and silicon. A method for making the coated article is also described.

BACKGROUND

1. Technical Field

The present disclosure relates to coated articles and a method formaking the coated articles.

2. Description of Related Art

The standard electrode potential of aluminum alloy or magnesium alloy isvery low. When the aluminum alloy or magnesium alloy substrate is coatedwith a layer using physical vapor deposition (PVD) technology, thesubstrate often suffers galvanic corrosion due to the high potentialdifference between the layer and the substrate. Furthermore, the layermade by PVD will have tiny openings such as pinholes and cracks, whichcan accelerate the galvanic corrosion of the substrate.

Therefore, there is room for improvement within the art.

BRIEF DESCRIPTION OF THE FIGURE

Many aspects of the coated article and the method for making the coatedarticle can be better understood with reference to the followingdrawings. The components in the drawings are not necessarily drawn toscale, the emphasis instead being placed upon clearly illustrating theprinciples of the coated article and the method. Moreover, in thedrawings like reference numerals designate corresponding partsthroughout the several views. Wherever possible, the same referencenumbers are used throughout the drawings to refer to the same or likeelements of an embodiment.

FIG. 1 is a cross-sectional view of an exemplary embodiment of a coatedarticle;

FIG. 2 is a schematic view of a vacuum sputtering device for fabricatingthe coated article in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a coated article 10 according to an exemplary embodiment.The coated article 10 includes a substrate 11 and an anti-corrosionlayer 13 formed on the substrate 11.

The substrate 11 is made of aluminum alloy or magnesium alloy.

The anti-corrosion layer 13 is an amorphous alloy layer, which containselements of iron, chromium, boron and M, wherein M is one or moreselected from the group consisting of phosphorus, carbon and silicon.The anti-corrosion layer 13 contains by atomic percentage, about 68% toabout 72% of iron, about 8% to about 12% of chromium, about 10% to about14% of boron, and about 2% to about 14% of M. The anti-corrosion layer13 may be formed by a vacuum sputtering process. The anti-corrosionlayer 13 has a thickness of about 800 nm to about 1200 nm.

The coated article 10 further includes a decorative layer 15 formed onthe anti-corrosion layer 13. The decorative layer 15 is composed of acompound selected from the group consisting of carbide of titanium,chromium or zirconium, nitride of titanium, chromium or zirconium, andoxide of titanium, chromium or zirconium. The decorative layer 15 may beformed by a vacuum sputtering process. The decorative layer 15 has athickness of about 400 nm to about 600 nm.

FIG. 2 shows a vacuum sputtering device 20, which includes a vacuumchamber 21 and a vacuum pump 30 connected to the vacuum chamber 21. Thevacuum pump 30 evacuates the vacuum chamber 21. The vacuum chamber 21has first targets 23, second targets 24 and a rotary rack (not shown)positioned therein. The rotary rack holding the substrate 11 revolvesalong a circular path 25, and the substrate 11 is also rotated about itsown axis while being carried by the rotary rack. The first targetcontains about 68% to about 72% of iron, about 8% to about 12% ofchromium, about 10% to about 14% of boron, and about 2% to about 14% ofM by atomic percentage. The second target can be made of titanium,chromium or zirconium.

A method for making the coated article 10 may include the followingsteps:

The substrate 11 is pretreated. The pre-treating process may includewiping the surface of the substrate 11 with alcohol and deionized water,to remove impurities such as grease or dirt from the substrate 11. Then,the substrate 11 is dried.

The anti-corrosion layer 13 may be vacuum sputtered on the substrate 11.Vacuum sputtering of the anti-corrosion layer 13 is carried out in thevacuum chamber 21. The substrate 11 is positioned on the rotary rack.The vacuum chamber 21 is evacuated to about 8.0×10⁻³ Pa and is heated toa temperature of about 100° C. to about 150° C. Argon gas (Ar) is usedas the sputtering gas and is fed into the vacuum chamber 21 at a flowrate of about 150 sccm to about 300 sccm. The first targets 23 aresupplied with electrical power of about 5 kw to about 10 kw. A negativebias voltage of about −50 V to about −300 V is applied to the substrate11. Deposition of the anti-corrosion layer 13 takes a total of about 30min to about 90 min. The anti-corrosion layer 13 contains about 68% toabout 72% of iron, about 8% to about 12% of chromium, about 10% to about14% of boron, and about 2% to about 14% of M by atomic percentage.

The decorative layer 15 is vacuum sputtered on the anti-corrosion layer13. Vacuum sputtering of the decorative layer 15 is carried out in thevacuum chamber 21. The first targets 23 are powered off and the secondtargets 24 are supplied with electrical power of about 5 kw to about 8kw. Nitrogen (N₂) is used as the reaction gas and is fed into the vacuumchamber 21 at a flow rate of about 60 sccm to about 150 sccm. The flowrate of argon, temperature of the vacuum chamber 21 and the negativebias voltage are the same as vacuum sputtering of the anti-corrosionlayer 13. Deposition of the decorative layer 15 takes a total of about20 min to about 40 min.

EXAMPLE 1

The vacuum sputtering device 20 in example 1 was a medium frequencymagnetron sputtering device.

The substrate 11 was made of magnesium alloy.

Sputtering to form the anti-corrosion layer 13 on the substrate 11 tookplace, wherein the vacuum chamber 21 was heated to a temperature ofabout 100° C. Ar was fed into the vacuum chamber 21 at a flow rate ofabout 180 sccm. The first targets 23 were supplied with a power of about8 kw, and a negative bias voltage of about −75 V was applied to thesubstrate 11. Deposition of the anti-corrosion layer 13 took a total ofabout 45 min. The anti-corrosion layer 13 had a thickness of about 800nm.

Sputtering to form the decorative layers 15 on the anti-corrosion layer13 took place, wherein the second targets 24 were supplied with a powerof about 8 kw. N₂ was fed into the vacuum chamber 21 at a flow rate ofabout 100 sccm. Other conditions were substantially the same as vacuumsputtering of the anti-corrosion layer 13. The deposition of thedecorative layers 15 took a total of about 20 min. The decorative layers15 had a thickness of about 600 nm.

EXAMPLE 2

The vacuum sputtering device 20 in example 2 was the same in example 1.

The substrate 11 was made of aluminum alloy.

Sputtering to form the anti-corrosion layer 13 on the substrate 11 tookplace, wherein the vacuum chamber 21 was heated to a temperature ofabout 100° C. Ar was fed into the vacuum chamber 21 at a flow rate ofabout 250 sccm. The first targets 23 were supplied with a power of about10 kw, and a negative bias voltage of about −100 V was applied to thesubstrate 11. Deposition of the anti-corrosion layer 13 took a total ofabout 45 min. The anti-corrosion layer 13 had a thickness of about 1200nm.

Sputtering to form the decorative layers 15 on the anti-corrosion layer13 took place, wherein the second targets 24 were supplied with a powerof about 8 kw. N₂ was fed into the vacuum chamber 21 at a flow rate ofabout 120 sccm. Other conditions were substantially the same as vacuumsputtering of the anti-corrosion layer 13. The deposition of thedecorative layers 15 took a total of about 20 min. The decorative layers15 had a thickness of about 500 nm.

When the coated article 10 is in a corrosive environment, theanti-corrosion layer 13 and the substrate 11 will become cathode andanode of the galvanic corrosion respectively due to the high potentialdifference between the anti-corrosion layer 13 and the substrate 11. Theanti-corrosion layer 13 quickly forms an oxide passivation layer in thegalvanic corrosion process and protects the substrate 11 from furthergalvanic corrosion. Thus, the corrosion resistance of the coated article10 is improved. The decorative layer 15 has stable properties and givesthe coated article 10 a long lasting aesthetically pleasing appearance.

It is believed that the exemplary embodiment and its advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the disclosure or sacrificing all of its advantages, theexamples hereinbefore described merely being preferred or exemplaryembodiment of the disclosure.

1. A coated article, comprising: a substrate being made of aluminumalloy or magnesium alloy; and an anti-corrosion layer formed on thesubstrate, the anti-corrosion layer being an amorphous alloy layer andcontaining about 68% to about 72% of iron, about 8% to about 12% ofchromium, about 10% to about 14% of boron, and about 2% to about 14% ofM by atomic percentage; wherein M being one or more selected from thegroup consisting of phosphorus, carbon and silicon.
 2. The coatedarticle as claimed in claim 1, wherein the anti-corrosion layer has athickness of about 800 nm to about 1200 nm.
 3. A coated article,comprising: a substrate being made of aluminum alloy or magnesium alloy;an anti-corrosion layer formed on the substrate, the anti-corrosionlayer being an amorphous alloy layer and containing about 68% to about72% of iron, about 8% to about 12% of chromium, about 10% to about 14%of boron, and about 2% to about 14% of M by atomic percentage; and adecorative layer formed on the anti-corrosion layer; wherein M being oneor more selected from the group consisting of phosphorus, carbon andsilicon.
 4. The coated article as claimed in claim 3, wherein theanti-corrosion layer has a thickness of about 800 nm to about 1200 nm.5. The coated article as claimed in claim 3, wherein the decorativelayer is composed of a compound selected from the group consisting ofcarbide of titanium, chromium or zirconium, nitride of titanium,chromium or zirconium, and oxide of titanium, chromium or zirconium. 6.The coated article as claimed in claim 3, wherein the decorative layerhas a thickness of about 400 nm to about 600 nm.
 7. A method for makinga coated article, comprising: providing a substrate; forming ananti-corrosion layer on the substrate; the anti-corrosion layer being anamorphous alloy layer and containing about 68% to about 72% of iron,about 8% to about 12% of chromium, about 10% to about 14% of boron, andabout 2% to about 14% of M by atomic percentage, and M being one or moreselected from the group consisting of phosphorus, carbon and silicon;and forming a decorative layer on the anti-corrosion layer.
 8. Themethod as claimed in claim 7, wherein magnetron sputtering theanti-corrosion layer uses argon gas as the sputtering gas and the argongas has a flow rate of about 150 sccm to about 300 sccm; magnetronsputtering the anti-corrosion layer is carried out at a temperature ofabout 100° C. to about 150° C.; uses first targets containing about 68%to about 72% of iron, about 8% to about 12% of chromium, about 10% toabout 14% of boron, and about 2% to about 14% of M by atomic percentageand the first targets are supplied with a power of about 5 kw to about10 kw; a negative bias voltage of about −50 V to about −300 V is appliedto the substrate.
 9. The method as claimed in claim 8, wherein vacuumsputtering the anti-corrosion layer takes about 30 min to about 90 min.10. The method as claimed in claim 7, wherein magnetron sputtering thedecorative layer uses argon gas as the sputtering gas and the argon gashas a flow rate of about 150 sccm to about 300 sccm; uses nitrogen asthe reaction gas and the nitrogen has a flow rate of about 60 to about150 sccm; magnetron sputtering the decorative layer is carried out at atemperature of about 100° C. to about 150° C.; uses second targets madeof titanium, chromium or zirconium and the second targets are suppliedwith a power of about 5 kw to about 8 kw; a negative bias voltage ofabout −50 V to about −300 V is applied to the substrate.
 11. The methodas claimed in claim 10, wherein vacuum sputtering the decorative layertakes about 20 min to about 40 min.